An exhaust gas generated from incineration facilities for incinerating wastes such as industrial wastes and general home garbage contains various chlorinated organic compounds such as dioxins, polychlorobiphenyls, chlorophenol and chlorobenzene.
Herein, the word, dioxins, is a general term of polychlorodibenzo-para-dioxins (PCDDs), polychlorodibenzofurans (PCDFs) and the like, and is an environmental pollutant which is extremely toxic, as well known. Inter alia, 2,3,7,8-tetrachlorodibenzo-para-dioxin (T4CDD) is known as a most toxic substance. In addition, polychlorobiphenyls are similarly an environmental pollutant which is considerably toxic. Inter alia, coplanar polychlorobiphenyls (Co-PCBs) are recognized as a most toxic substance like dioxins. In the present application, the word “dioxins” is used to include coplanar polychlorobiphenyls (Co-PCBs) in addition to polychlorodibenzo-para-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) according to Article 2 of “Law Concerning Special Measures against Dioxins” established in 1999 as Law No.105 in Japan.
On the other hand, although chlorinated organic compounds such as chlorophenol and chlorobenzene are less toxic as compared with dioxins, it has been found that they are easily converted into dioxins under certain conditions, for example, using various elements contained in fly ashes as catalyst in an incinerator in a temperature range of an exhaust gas. Therefore, they are recognized as environmental pollutants like dioxins. For this reason, from a viewpoint of environmental protection, it becomes an urgent issue to establish a countermeasure for removing the aforementioned various chlorinated organic compounds from a fluid such as an exhaust gas and waste-water. At the same time, it is also urgent in global scale to establish a procedure for analyzing chlorinated organic compounds contained in such a fluid.
Meanwhile, when chlorinated organic compounds contained in a fluid are analyzed, first, it is necessary to obtain a sample precisely and exactly from a fluid to be analyzed. For example, when chlorinated organic compounds contained in an exhaust gas are analyzed, it is necessary to collect a prescribed amount of a sample gas from a space containing the exhaust gas, for example, a flue through which the exhaust gas is flown, and assuredly capture all various chlorinated organic compounds contained in this sample gas without leakage. In particular, the aforementioned dioxins, which are environmental pollutants, are contained in the sample gas at an extremely small amount, and dioxins are in various forms such as particulate form and gaseous form, and there are many kinds of dioxins. Therefore, without precise collection of them, analysis results having high reliance cannot be expected. Further, since there is a possibility that coplanar polychlorobiphenyl is contained in the atmospheric air at a large amount, when a sample gas is contaminated with the air containing coplanar polychlorobiphenyl, analysis results having high reliance cannot be expected similarly. For this reason, in order to guarantee the accuracy of the analysis results, Japan, US and each country of Europe respectively have been officially establishing a method, for example, for collecting a necessary sample for analyzing a chlorinated organic compound such as dioxins contained in an exhaust gas.
For example, Japanese Industrial Standard JIS K 0311:1999 established on Sep. 20, 1999 stipulates “Method for determination of tetra- through octa-chlorodibenzo-p-dioxins, tetra- through octa-chlorodibenzofurans and coplanar polychlorobiphenyls in stationary source emissions”, and specifically exemplifies a device for collecting a sample gas including a chlorinated organic compound such as dioxins therein. This collecting device is provided mainly with a collecting tube for collecting a sample gas from a flue of an incineration equipment through which an exhaust gas is flown, a first captor provided with a filter material for capturing a chlorinated organic compound mainly in a particulate form contained in the sample gas collected by the collecting tube, and a second captor for capturing a chlorinated organic compound in a gaseous form which is hardly captured by the first captor. Herein, the second captor is provided mainly with a liquid capturing portion composed of a plurality of glass impingers containing an absorbent liquid and an adsorptive capturing portion arranged with an adsorbent (e.g. styrene-divinylbenzene copolymer sold under trade name of XAD-2), and is constructed that a chlorinated organic compound in a gaseous form which is not captured by the first captor can be captured by the absorbent liquid contained in the impingers and the adsorbent.
Since such a collecting device has a complicated construction provided with the first captor and the second captor, and is expensive because of use of many glass instruments, the device is utilized repeatedly in many cases. In this case, since it is required to keep the respective members such as impingers clean in order to retain the reliance of measurement data, a preparatory work such as washing procedure before collection of a sample gas becomes very troublesome. In addition, upon capturing of a chlorinated organic compound in a gaseous form contained in a sample gas by the second captor, it is necessary to cool the second captor using a coolant such as dry ice, and the procedure of collecting a sample itself becomes very complicated. Further, after collection of a sample gas, it is necessary to extract a chlorinated organic compound captured by the first captor and the second captor. Herein, since it is necessary to extract individually the chlorinated organic compounds captured by the first captor and the second captor having a complicated construction, respectively, the extraction procedure itself is troublesome, and it takes a long time until completion. In addition, the reliance of analysis results depends on skill of extraction procedure in many cases. Further, since this collecting device is composed of two types of captors of the first captor and the second captor, the device is inevitably scaled up. Moreover, since the device uses many glass instruments and therefore is easily damaged, handling at sample gas collection and conveyance are also difficult.
On the other hand, Environmental Protection Agency (EPA) of USA and European Committee for Standardization (CEN) also stipulate their own official methods. However, collecting devices shown therein are different from the aforementioned Japanese device in details, but are slightly different in respect of complicated construction and difficult handling.
The object of the present invention is to simultaneously capture and collect various kinds of chlorinated organic compounds in both particulate form and gaseous form contained in a fluid, and easily extract the collected chlorinated organic compounds.